Four short links: 20 July 2011

Meaningful Subsets, iPhone Reading, JSON Parser, The Epiphanator

Random Khan Exercises — elegant hack to ensure repeatability for a user but difference across users. Note that they need these features of exercises so that they can perform meaningful statistical analyses on the results.

Float, the Netflix of Reading (Wired) — an interesting Instapaper variant with a stab at an advertising business model. I would like to stab at the advertising business model, too. What I do like is that it’s trying to do something with the links that friends tweet, an unsolved problem for your humble correspondent. (via Steven Levy

Facebook and the Epiphanator (NY Magazine) — Paul Ford has a lovely frame through which to see the relationship between traditional and social media. So it would be easy to think that the Whole Earthers are winning and the Epiphinators are losing. But this isn’t a war as much as a trade dispute. Most people never chose a side; they just chose to participate. No one joined Facebook in the hope of destroying the publishing industry.